The present invention relates to ground transportation systems, and, more particularly, to transportation systems using pneumatic propulsion systems.
Due to many factors, the cost of transporting passengers and cargo over long distances has, in the last few years dramatically increased. As this cost continues to rise, shippers and transporters have sought more efficient ways of shipping cargo and transporting passengers.
The efficiency of known ground based systems, such as railroads and highways, is limited by several factors. One important factor is the speed with which such systems can move the cargo and/or passengers from place to place. Modern technology, such as computer technology and high-speed trains, have done much to speed up railroad movement, but railroads are still using the same basic concept of a wheeled vehicle being propelled over a track system which has been in use for decades. The friction factors and other mechanical losses inherent in such systems prevent them from attaining the speeds required for efficient ground transportation.
Friction losses involved in air transportation systems are much lower then those found in ground based systems, and therefore air transportation is capable of achieving speeds which greatly exceed those obtained by ground based transportation systems. However, air transportation systems have several drawbacks of their own. For example, airports are generally located far away from cities and/or connecting ground transportation systems. Furthermore, air transportation is often at the mercy of the vagaries of the weather and is hence often unreliable. A further drawback to air transportation is the cost involved due to the great number of people required to support air flights. These people include, for example, pilots, navigators and the ground support crews. Railroad systems are not similarly cost limited, but cannot obtain the speeds required to effectively ship over long distances.
Furthermore, both air and railroad systems suffer from cargo losses due to theft and to highjacking, and both are dependent on hydrocarbon fuels for their means of propulsion. Recently, the cost of such hydrocarbon fuels has increased to a level which could make the cost of propelling the vehicles prohibitive in itself, even without including the other above-mentioned costs.
Therefore, an ideal cargo and passenger transportation system would be one which combines the high speed movement of an airplane with the reliability and convenience of a ground based system. A ground based transportation system similar to a railroad yet having friction factors in the order of those involved with air flight would effect such a combination. Therefore, a ground based system which could achieve speeds in the order of air flights could be developed.
Some systems have been proposed which purportedly produce efficient high-speed ground based transportation. Among these systems are the pneumatic propulsion systems. As used herein, a pneumatically powered system is one in which a vehicle is propelled in a duct as a free piston therein by establishing differential pressure between the front and rear of the vehicle in the duct. Thus, with gas in the duct in front of the vehicle at a lower pressure, and gas in the duct at a pressure which is high relative to the front gas pressure located at the rear of the vehicle, the vehicle is rapidly propelled as a free piston through the duct.
The pneumatically powered systems do not depend on hydrocarbon fuels and ground speeds approaching, and even potentially exceeding, those of air transportation systems are feasible.
However, the vehicles in most of the known pneumatically powered ground transportation systems ride on tracks or slides and hence suffer drawbacks due to friction which are similar to those drawbacks discussed above with reference to railroad transportation systems. Furthermore, due to the speeds proposed for these vehicles, shocks to, and vibration of, cargo and passengers may reach intolerably high levels. Noise may also reach intolerable levels. Frictional heating may also damage the tracks and/or the vehicle wheels thus creating safety and maintenance problems. Thus, known pneumatically powered systems utilizing tracks or slides to support and guide the vehicle have inherent drawbacks which have prevented them from gaining wide acceptance.
The so-called ground effect machines eliminate frictional resistance to vehicle movement by supporting the vehicle on pressurized air ejected from the bottom of the vehicle. However, such vehicles are not compatible with pneumatically powered vehicle systems as the pressurized air ejected from the vehicle will inhibit or destroy the vacuum conditions present ahead of the vehicle. Hence, the ground effect machine may eliminate frictional resistance to movement of the vehicle, but in doing so, may also eliminate the source of propulsion for the vehicle. Furthermore, the equipment required to produce the stream of pressurized air from the vehicle bottom must be carried onboard the vehicle, thus reducing the space available for passenger or cargo transportation.
The present invention enables a pneumatically powered vehicle to ride in a film of gas thereby reducing the energy losses due to friction to essentially negligible levels.